124-526: Plethodon is a genus of salamanders in the family Plethodontidae . They are commonly known as woodland salamanders . All members of the genus are endemic to North America (Canada and the United States). They have no aquatic larval stage. In some species, such as the red-backed salamander ( Plethodon cinereus ). Young hatch in the adult form. Members of Plethodon primarily eat small invertebrates. The earliest known fossils of this genus are from
248-572: A U.C. elementary school science project which recommended that science be taught to children as early as six. In conjunction with the Sierra Club he produced two educational films: Nature Next Door (1962) and No Room for Wilderness? (1967). Stebbins co-authored revisions of the widely used textbooks General Zoology (5th ed.,1972; 6th ed., 1979) and Elements of Zoology (4th ed., 1974), books originally written by Tracy Storer and Robert Usinger . Someday Robert Stebbins may be remembered as
372-479: A biology professor there. Stebbins returned with enthusiasm despite the perceived lack of job security, remarking in 1985: "I was cautious because of the Great Depression, but I was determined to pursue biology even if it meant standing on a corner with a tin cup." He switched his major to zoology and graduated in 1940 with highest honors. After graduating, Stebbins split his time between a summer job as
496-413: A concealed site in flowing water, and these are usually guarded by an adult, normally the female. Many of the tropical climbing salamanders ( Bolitoglossa ) and lungless salamanders (Plethodontinae) lay a small number of large eggs on land in a well-hidden spot, where they are also guarded by the mother. Some species such as the fire salamanders ( Salamandra ) are ovoviviparous , with the female retaining
620-405: A decade of conservation efforts. Stebbins and colleagues studied the diversity of organisms in and around ORV areas, communicated research to Bureau of Land Management officials, and petitioned President Jimmy Carter to limit all-terrain vehicle use in deserts. Stebbins faced opposition from ORV riders and their lobbyists: American Motorcyclist magazine called him a "staunch abolitionist in
744-586: A flash of warning hue on its underside. The red eft, the brightly colored terrestrial juvenile form of the eastern newt ( Notophthalmus viridescens ), is highly poisonous. It is avoided by birds and snakes, and can survive for up to 30 minutes after being swallowed (later being regurgitated). The red salamander ( Pseudotriton ruber ) is a palatable species with a similar coloring to the red eft. Predators that previously fed on it have been shown to avoid it after encountering red efts, an example of Batesian mimicry . Other species exhibit similar mimicry. In California,
868-518: A group of amphibians typically characterized by their lizard -like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All ten extant salamander families are grouped together under the order Urodela from the group Caudata . Urodela is a scientific Latin term based on the Ancient Greek οὐρά δήλη : ourà dēlē "conspicuous tail". Caudata
992-416: A hissing sound, while the sirens sometimes produce quiet clicks, and can resort to faint shrieks if attacked. Similar clicking behaviour was observed in two European newts Lissotriton vulgaris and Ichthyosaura alpestris in their aquatic phase. Vocalization in salamanders has been little studied and the purpose of these sounds is presumed to be the startling of predators. Respiration differs among
1116-438: A lateral row. This may provide an aposematic signal that makes the spines more visible. When the danger has passed, the ribs retract and the skin heals. Although many salamanders have cryptic colors so as to be unnoticeable, others signal their toxicity by their vivid coloring . Yellow, orange, and red are the colors generally used, often with black for greater contrast. Sometimes, the animal postures if attacked, revealing
1240-665: A long body, a laterally flattened tail with dorsal and ventral fins and in some species limb-buds or limbs. Pond-type larvae may have a pair of rod-like balancers on either side of the head, long gill filaments and broad fins. Stream-type larvae are more slender with short gill filaments—in Rhyacotriton and Onychodactylus, and some species in Batrachuperus, the gills and gill rakers are extremely reduced, narrower fins and no balancers, but instead have hind limbs already developed when they hatch. The tadpoles are carnivorous and
1364-517: A minute fragment of skin is deadly. In feeding trials, fish, frogs, reptiles, birds, and mammals were all found to be susceptible. Mature adults of some salamander species have "nuptial" glandular tissue in their cloacae , at the base of their tails, on their heads or under their chins. Some females release chemical substances , possibly from the ventral cloacal gland, to attract males, but males do not seem to use pheromones for this purpose. In some plethodonts , males have conspicuous mental glands on
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#17327755780461488-519: A naturalist at Lassen Volcanic National Park and pursuing graduate school at UCLA. Over the next few years he also obtained teaching credentials in junior college, high school, and elementary education. Stebbins initially planned to study birds, with an eye towards roadrunners , but felt the field of ornithology was too crowded, while herpetology, the study of reptiles and amphibians, offered more opportunities for new research. Cowles became his graduate advisor. The main focus of Stebbins' graduate research
1612-609: A reasonable size. Large species such as the Japanese giant salamander ( Andrias japonicus ) eat crabs, fish, small mammals, amphibians, and aquatic insects. In a study of smaller dusky salamanders ( Desmognathus ) in the Appalachian Mountains , their diet includes earthworms , flies , beetles , beetle larvae, leafhoppers , springtails , moths , spiders , grasshoppers , and mites . Cannibalism sometimes takes place, especially when resources are short or time
1736-471: A research expedition and studied the ecology and behavior of marine iguanas and lava lizards . Also on the expedition was Roger Tory Peterson , who recalled "While the rest of were enjoying high adventure on the more remote islands and sea-girt rocks, he patiently snared 200 frisky lizards with a noose of thread suspended from a rod. He took their cloacal temperatures, marked them with dye, and then dosed them with radioactive iodine, which enabled him to locate
1860-433: A second. In some species, the tongue is attached anteriorly to the floor of the mouth, while in others, it is mounted on a pedicel. It is rendered sticky by secretions of mucus from glands in its tip and on the roof of the mouth. High-speed cinematography shows how the tiger salamander ( Ambystoma tigrinum ) positions itself with its snout close to its prey. Its mouth then gapes widely, the lower jaw remains stationary, and
1984-571: A series of papers from the 1950s through the 1970s exploring the parietal eye of reptiles (also called the "third eye", a tiny light-sensitive organ on the forehead) and the associated pineal gland , both of which are now known to influence circadian rhythms . Aided by a Senior Postdoctoral Fellowship from the National Science Foundation, Stebbins and colleagues found that lizards with the parietal eye surgically removed changed their behavior: they became active much earlier in
2108-678: A short period of time and involves the closing of the gill slits and the loss of structures such as gills and tail fins that are not required as adults. At the same time, eyelids develop, the mouth becomes wider, a tongue appears, and teeth are formed. The aqueous larva emerges onto land as a terrestrial adult. Not all species of salamanders follow this path. Neoteny , also known as paedomorphosis, has been observed in all salamander families, and may be universally possible in all salamander species. In this state, an individual may retain gills or other juvenile features while attaining reproductive maturity. The changes that take place at metamorphosis are under
2232-514: A simplified retinal structure, and in cave dwellers such as the Georgia blind salamander , they are absent or covered with a layer of skin. In amphibious species, the eyes are a compromise and are nearsighted in air and farsighted in water. Fully terrestrial species such as the fire salamander have a flatter lens which can focus over a much wider range of distances. To find their prey, salamanders use trichromatic color vision extending into
2356-640: A single species that in most locations interbreed where two forms co-occur, creating hybrids that partially resemble both forms. However, at the southern edge of the Central Valley, where the Sierra foothill populations come into contact with those of the Coast Range, the populations do not interbreed, instead acting as distinct species. This phenomenon is known as a ring speciation , with different populations representing different stages of speciation ,
2480-407: A small lizard, having a basal tetrapod body form with a cylindrical trunk, four limbs, and a long tail. Except in the family Salamandridae, the head, body, and tail have a number of vertical depressions in the surface which run from the mid-dorsal region to the ventral area and are known as costal grooves . Their function seems to be to help keep the skin moist by channeling water over the surface of
2604-437: A top predator since the introduction of locally exotic species such as Nile tilapia and carp. Tilapia and carp directly compete with axolotls by consuming their eggs, larvae, and juveniles. Climate change has also immensely affected axolotls and their populations throughout the southern Mexico area. Due to its proximity to Mexico City , officials are currently working on programs at Lake Xochimilco to bring in tourism and educate
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#17327755780462728-520: Is advanced into the salamander's mouth, the teeth tips relax and bend in the same direction, encouraging movement toward the throat, and resisting the prey's escape. Many salamanders have patches of teeth attached to the vomer and the palatine bones in the roof of the mouth, and these help to retain prey. All types of teeth are resorbed and replaced at intervals throughout the animal's life. A terrestrial salamander catches its prey by flicking out its sticky tongue in an action that takes less than half
2852-566: Is another large, long-lived species with dwindling numbers and fewer juveniles reaching maturity than previously. Another alarming finding is the increase in abnormalities in up to 90% of the hellbender population in the Spring River watershed in Arkansas. Habitat loss, silting of streams, pollution and disease have all been implicated in the decline and a captive breeding programme at Saint Louis Zoo has been successfully established. Of
2976-459: Is being undertaken to assess the status of these salamanders, and to better understand the factors involved in their population declines, with a view to taking action. Ambystoma mexicanum , an aquatic salamander, is a species protected under the Mexican UMA (Unit for Management and conservation of wildlife) as of April 1994. Another detrimental factor is that the axolotl lost their role as
3100-624: Is internal. As a general rule, salamanders with internal fertilization have indirect sperm transfer, but in species like the Sardinian brook salamander , the Corsican brook salamander , the Caucasian salamander and the Pyrenean brook salamander , the male transfer his sperm directly into the female cloaca. For the species with indirect sperm transfer, the male deposits a spermatophore on
3224-417: Is larger than that of the female, is used during the amplexus embrace to propel the mating couple to a secluded location. In terrestrial species, the tail moves to counterbalance the animal as it runs, while in the arboreal salamander and other tree-climbing species, it is prehensile . The tail is also used by certain plethodontid salamanders that can jump, to help launch themselves into the air. The tail
3348-435: Is limited. Tiger salamander tadpoles in ephemeral pools sometimes resort to eating each other, and are seemingly able to target unrelated individuals. Adult blackbelly salamanders ( Desmognathus quadramaculatus ) prey on adults and young of other species of salamanders, while their larvae sometimes cannibalise smaller larvae. Most species of salamander have small teeth in both their upper and lower jaws. Unlike frogs , even
3472-465: Is not just limited to limbs but extends to vital organs such as the heart, jaw, and parts of the spinal cord, showing their uniqueness compared to different types of vertebrates. This ability is most remarkable for occurring without any type of scarring. This has made salamanders an invaluable model organism in scientific research aimed at understanding and achieving regenerative processes for medical advancements in human and animal biology. Members of
3596-455: Is restricted to the slightly cooler and wetter conditions in north-facing cove forests in the southern Appalachians, and to higher elevations above 900 m (3,000 ft), while the former is more adaptable, and would be perfectly able to inhabit these locations, but some unknown factor seems to prevent the two species from co-existing. One species, the Anderson's salamander , is one of
3720-773: Is the Latin for "tailed ones", from cauda : "tail". Salamander diversity is highest in eastern North America , especially in the Appalachian Mountains ; most species are found in the Holarctic realm , with some species present in the Neotropical realm . Salamanders never have more than four toes on their front legs and five on their rear legs, but some species have fewer digits and others lack hind limbs. Their permeable skin usually makes them reliant on habitats in or near water or other cool, damp places. Some salamander species are fully aquatic throughout their lives, some take to
3844-413: Is used in courtship and as a storage organ for proteins and lipids. It also functions as a defense against predation, when it may be lashed at the attacker or autotomised when grabbed. Unlike frogs, an adult salamander is able to regenerate limbs and its tail when these are lost. The skin of salamanders, in common with other amphibians, is thin, permeable to water, serves as a respiratory membrane, and
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3968-407: Is well-supplied with glands. It has highly cornified outer layers, renewed periodically through a skin shedding process controlled by hormones from the pituitary and thyroid glands. During moulting, the skin initially breaks around the mouth, and the animal moves forward through the gap to shed the skin. When the front limbs have been worked clear, a series of body ripples pushes the skin toward
4092-613: The Contra Costa Times as one of 10 environmental leaders deemed "national treasures" for their activism. Other research included field work in Colombia, South Africa, and Australia, and the description of several species: the Jemez Mountains salamander , southern torrent salamander , yellow-eyed ensatina , and the panamint alligator lizard . Two salamanders were named in his honor during his time at Berkeley:
4216-706: The Alaska Panhandle . They had an exclusively Laurasian distribution until Bolitoglossa invaded South America from Central America, probably by the start of the Early Miocene , about 23 million years ago. They also lived on the Caribbean Islands during the early Miocene epoch, confirmed by the discovery of Palaeoplethodon hispaniolae , found trapped in amber in the Dominican Republic . Vertebrae fossils recovered from
4340-524: The Hemphillian of Tennessee in the United States. Plethodon is part of the family Plethodontidae (lungless salamanders) and the subfamily Plethodontinae . The genus Plethodon can be divided into two subgenera : the nominal subgenus Plethodon , which includes up to 49 eastern species (the bulk of diversity in the genus), and the subgenus Hightonia , which includes 9 species native to
4464-943: The Holarctic and Neotropical regions, not reaching south of the Mediterranean Basin , the Himalayas , or in South America the Amazon Basin . They do not extend north of the Arctic tree line , with the northernmost Asian species, Salamandrella keyserlingii , which can survive long-term freezing at −55 °C, occurring in the Siberian larch forests of Sakha and the most northerly species in North America, Ambystoma laterale , reaching no farther north than Labrador and Taricha granulosa not beyond
4588-618: The Murgon fossil site have been tentatively attributed to that of a Salamander, though its true identity is disputed. If the vertebrae truly belong to a Salamander, they would represent the only Salamanders in Australia . There are about 760 living species of salamander. One-third of the known salamander species are found in North America. The highest concentration of these is found in the Appalachian Mountains region, where
4712-1455: The Rocky Mountains of Idaho , and one ( P. neomexicanus ) in the Jemez Mountains of New Mexico . All 58 Plethodon species listed in alphabetical order of specific name : Lazell , 1998 Grobman , 1944 Highton & Peabody , 2000 Grobman, 1944 Mead , Clayton , Nauman , Olson & Pfrender , 2005 Highton, 1984 C. Pope & S. Pope , 1951 Highton, 1989 Highton & Peabody, 2000 Mittleman , 1951 ( J. Green , 1818) ( Harlan , 1825) C. Pope & J. Fowler , 1949 Cope , 1889 Bishop , 1934 Highton, 1999 Van Denburgh , 1916 Duncan & Highton, 1959 (J. Green, 1818) Allen & Neill , 1949 Highton, 1972 Thurow , 1957 Slater & Slipp , 1940 Newman , 1954 Blatchley , 1901 Mittleman, 1951 Highton, 1989 Highton, 1989 Burns , 1954 Highton & Peabody, 2000 Brimley , 1912 Highton, 1989 Highton & Peabody, 2000 Stebbins & Riemer , 1950 N.B. Green , 1938 Highton, 1989 Dunn & Heinze , 1933 Felix , Wooten , Pierson & Camp , 2019 Wynn , Highton & Jacobs , 1988 Highton, 1972 Netting & Mittleman, 1938 Highton, 1989 Highton, 1989 Grobman, 1944 Salamander Cryptobranchoidea Salamandroidea Salamanders are
4836-595: The Sierra Nevada and Coast Ranges of California but absent in the Central Valley. Finding the salamanders in Berkeley very different from the ones he was used to seeing in the mountains of Southern California, he embarked upon a research program examining color differences throughout California. In his resulting monograph, published in 1949, he proposed that the color varieties—many previously regarded as distinct species—were actually various races or subspecies of
4960-805: The Tehachapi slender salamander ( Batrachoseps stebbinsi ) and the Sonora tiger salamander ( Ambystoma tigrinum stebbinsi ). Over his 32 years at Berkeley, Stebbins was the advisor to 29 graduate students, including Wade Fox , Richard G. Zweifel , and R. Bruce Bury . Upon his retirement from UC Berkeley in 1978, Stebbins was awarded the highest faculty honor, the Berkeley Citation. After retiring, Stebbins remained active in painting, conservation, and education, and continued to make natural history observations. He revised his well-known and widely used Field Guide in 1985 and again in 2003. He co-wrote
5084-668: The University of California, Berkeley , and became the first curator of herpetology at the Museum of Vertebrate Zoology , where he would remain throughout his career. The first faculty member to teach herpetology at Berkeley, he wrote new lab manuals, created the herpetology teaching collection, and co-taught a popular course on vertebrate natural history. Stebbins soon became interested in Ensatina salamanders, which occur from British Columbia to Baja California and are present in both
Plethodon - Misplaced Pages Continue
5208-448: The University of California, Los Angeles (UCLA). He initially majored in civil engineering , thinking it a better career option than biology, but became unhappy with the program. Struggling with poor performance and health issues related to congenital heart problems, he took a leave for year and a half. During his time in recuperation, he turned his attention back to natural history, and was persuaded to return to UCLA by Raymond Cowles ,
5332-449: The amphiumas , metamorphosis is incomplete, and they retain one pair of gill slits as adults, with fully functioning internal lungs. Some species that lack lungs respire through gills. In most cases, these are external gills, visible as tufts on either side of the head. Some terrestrial salamanders have lungs used in respiration, although these are simple and sac-like, unlike the more complex organs found in mammals . Many species, such as
5456-401: The cloud forests of Guatemala and Mexico during the 1970s were found by 2009 to be rare. Few data have been gathered on population sizes over the years and, by intensive surveying of historic and suitable new locations, it has been possible to locate individuals of other species, such as Parvimolge townsendi , which had been thought to be extinct . Currently, the major lines of defense for
5580-495: The family Salamandridae are mostly known as newts and lack the costal grooves along the sides of their bodies typical of other groups. The skin of some species contains the powerful poison tetrodotoxin ; these salamanders tend to be slow-moving and have bright warning coloration to advertise their toxicity. Salamanders typically lay eggs in water and have aquatic larvae, but great variation occurs in their lifecycles . Some species in harsh environments reproduce while still in
5704-594: The lens or retina of the eye. Within only a few weeks of losing a piece of a limb, a salamander perfectly reforms the missing structure. Salamanders split off from the other amphibians during the mid- to late Permian, and initially were similar to modern members of the Cryptobranchoidea . Their resemblance to lizards is the result of symplesiomorphy , their common retention of the primitive tetrapod body plan, but they are no more closely related to lizards than they are to mammals. Their nearest relatives are
5828-638: The olm , have both lungs and gills as adults. In the Necturus , external gills begin to form as a means of combating hypoxia in the egg as egg yolk is converted into metabolically active tissue. Molecular changes in the mudpuppy during post-embryonic development primarily due to the thyroid gland prevent the internalization of the external gills as seen in most salamanders that undergo metamorphosis. The external gills seen in salamanders differs greatly from that of amphibians with internalized gills. Unlike amphibians with internalized gills which typically rely on
5952-502: The ultraviolet range, based on three photoreceptor types that are maximally sensitive around 450, 500, and 570 nm. The larvae, and the adults of some highly aquatic species, also have a lateral line organ, similar to that of fish, which can detect changes in water pressure. All salamanders lack middle ear cavity, eardrum and eustachian tube , but have an opercularis system like frogs, and are still able to detect airborne sound. The opercularis system consists of two ossicles:
6076-468: The 20 species of minute salamanders ( Thorius spp.) in Mexico, half are believed to have become extinct and most of the others are critically endangered. Specific reasons for the decline may include climate change, chytridiomycosis, or volcanic activity, but the main threat is habitat destruction as logging, agricultural activities, and human settlement reduce their often tiny, fragmented ranges. Survey work
6200-468: The 51 species ... covered than any preceding it," wrote Charles M. Bogert : "The maps provided for each species and subspecies are on the whole the most detailed and accurate of any thus far published." Stebbins' second herpetological field guide, Amphibians and Reptiles of Western North America (1954, McGraw-Hill ), was similarly praised. In 1964 Stebbins visited the Galápagos Islands on
6324-500: The California newt has many large poison glands in its skin, is diurnal, and is avoided by snakes. Some salamander species use tail autotomy to escape predators. The tail drops off and wriggles around for a while after an attack, and the salamander either runs away or stays still enough not to be noticed while the predator is distracted. The tail regrows with time, and salamanders routinely regenerate other complex tissues, including
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#17327755780466448-517: The Plethodontidae are thought to have originated in mountain streams. Here, vegetation zones and proximity to water are of greater importance than altitude. Only species that adopted a more terrestrial mode of life have been able to disperse to other localities. The northern slimy salamander ( Plethodon glutinosus ) has a wide range and occupies a habitat similar to that of the southern gray-cheeked salamander ( Plethodon metcalfi ). The latter
6572-819: The age of nine, his family moved to Southern California, living first in Pomona , then in Sherman Oaks, Los Angeles . Stebbins spent time hiking in the nearby Santa Monica Mountains , exploring the wildlife and amassing a collection of bird and mammal specimens which he prepared and mounted himself. Stebbins attended North Hollywood High School , where his father taught hygiene and agriculture. Robert graduated in 1933. He discovered his artistic talents around sixteen years old. His early work consisted of cartoons: he drew illustrations on classmates' clothing and contributed cartoons to youth magazines, winning several awards. Shortly after graduating high school, Stebbins enrolled in
6696-405: The animal of an approaching predator. Salamanders are usually considered to have no voice and do not use sound for communication in the way that frogs do. Before mating, they communicate by pheromone signaling; some species make quiet ticking, clicking, squeaks or popping noises, perhaps by the opening and closing of valves in the nose. Most salamanders lack vocal cords, but a larynx is present in
6820-422: The animal slippery and more difficult for predators to catch. Granular glands scattered on the upper surface, particularly the head, back, and tail, produce repellent or toxic secretions. Some salamander toxins are particularly potent. The rough-skinned newt ( Taricha granulosa ) produces the neurotoxin tetrodotoxin , the most toxic nonprotein substance known. Handling the newts does no harm, but ingestion of even
6944-404: The axolotl does not account for the overall lack of diversity. Evidence points toward a historical bottlenecking of Ambystoma that contributes to the variation issues and no longer a large genetic pool for it to pull from, thus raising concern for inbreeding due to lack of gene flow. One way researchers are looking into maintaining genetic diversity within the population is via cryopreservation of
7068-402: The body. Some aquatic species, such as sirens and amphiumas , have reduced or absent hind limbs, giving them an eel -like appearance, but in most species, the front and rear limbs are about the same length and project sideward, barely raising the trunk off the ground. The feet are broad with short digits, usually four on the front feet and five on the rear. Salamanders do not have claws, and
7192-478: The breeding season. Cave species dwelling in darkness lack pigmentation and have a translucent pink or pearlescent appearance. Salamanders range in size from the minute salamanders , with a total length of 27 mm ( 1 + 1 ⁄ 8 in), including the tail, to the Chinese giant salamander which reaches 1.8 m (6 ft) and weighs up to 65 kg (145 lb). All the largest species are found in
7316-455: The changing of pressures within the buccal and pharyngeal cavities to ensure diffusion of oxygen onto the gill curtain, neotenic salamanders such as Necturus use specified musculature, such as the levatores arcuum, to move external gills to keep the respiratory surfaces constantly in contact with new oxygenated water. Salamanders are opportunistic predators . They are generally not restricted to specific foods, but feed on almost any organism of
7440-457: The chin which are pressed against the females' nostrils during the courtship ritual. They may function to speed up the mating process, reducing the risk of its being disrupted by a predator or rival male. The gland at the base of the tail in Plethodon cinereus is used to mark fecal pellets to proclaim territorial ownership. Olfaction in salamanders plays a role in territory maintenance,
7564-472: The cloacae of females. The results of this research may be used in captive-breeding programmes for endangered species. The order name Urodela comes from the name Urodèles given by André Marie Constant Duméril in 1805, it is derived from the Greek words οὐρά ourā́ "tail" and δῆλος dēlos "visible, conspicuous" because of their "persistent" tails. Disagreement exists among different authorities as to
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#17327755780467688-424: The columella (equivalent to the stapes of higher vertebrates ) which is fused to the skull, and the operculum. An opercularis muscle connects the latter to the pectoral girdle, and is kept under tension when the animal is alert. The system seems able to detect low-frequency vibrations (500–600 Hz), which may be picked up from the ground by the fore limbs and transmitted to the inner ear. These may serve to warn
7812-617: The conservation of Salamanders includes both in situ and ex situ conservation methods. There are efforts in place for certain members of the Salamander family to be conserved under a conservation breeding program (CBP) but there should be research done ahead of time to determine if the Salamander species is actually going to value from the CBP, as researchers have noted that some species of amphibians completely fail in this environment. Various conservation initiatives are being attempted around
7936-498: The control of thyroid hormones and in obligate neotenes such as the axolotl ( Ambystoma mexicanum ), the tissues are seemingly unresponsive to the hormones. In other species, the changes may not be triggered because of underactivity of the hypothalamus-pituitary-thyroid mechanism which may occur when conditions in the terrestrial environment are too inhospitable. This may be due to cold or wildly fluctuating temperatures, aridity, lack of food, lack of cover, or insufficient iodine for
8060-425: The day, spent more time in the sun, and remained active much later than control lizards. Further studies over the next few decades focused on the parietal eye of the tuatara , the pineal gland's effects on lizard reproductive behavior, and parietal skull openings in fossil "mammal-like reptiles" such as Lystrosaurus . His work had implications beyond reptile biology: Nobel laureate Julius Axelrod , after reading
8184-548: The definition of the terms Caudata and Urodela. Some maintain that the Urodela should be restricted to the crown group , with the Caudata being used for the total group. Others restrict the name Caudata to the crown group and use Urodela for the total group. The former approach seems to be most widely adopted and is used in this article. Robert C. Stebbins Robert Cyril Stebbins (March 31, 1915 – September 23, 2013)
8308-603: The different species of salamanders, and can involve gills, lungs, skin, and the membranes of mouth and throat. Larval salamanders breathe primarily by means of gills , which are usually external and feathery in appearance. Water is drawn in through the mouth and flows out through the gill slits. Some neotenic species such as the mudpuppy ( Necturus maculosus ) retain their gills throughout their lives, but most species lose them at metamorphosis . The embryos of some terrestrial lungless salamanders, such as Ensatina , that undergo direct development, have large gills that lie close to
8432-465: The earlier Peterson Guide to eastern reptiles and amphibians by Roger Conant . The second edition, published in 1985, included several changes such as 37 new species, 12 new plates of illustrations, the inclusion of endemic species of the Baja California peninsula , and new common names chosen to enhance clarity. In his 1986 review, Sweet remarked on the frankness of imperfect knowledge: "For
8556-406: The egg's surface. When present in adult salamanders, lungs vary greatly among different species in size and structure. In aquatic, cold-water species like the torrent salamanders ( Rhyacotriton ), the lungs are very small with smooth walls, while species living in warm water with little dissolved oxygen, such as the lesser siren ( Siren intermedia ), have large lungs with convoluted surfaces. In
8680-755: The eggs are laid. In the Asiatic salamanders , the giant salamanders and Sirenidae , which are the most primitive groups, the fertilization is external. In a reproductive process similar to that of typical frogs, the male releases sperm onto the egg mass. These salamanders also have males that exhibit parental care , which otherwise only occur in females with internal fertilization. Three different types of egg deposition occur. Ambystoma and Taricha spp. spawn large numbers of small eggs in quiet ponds where many large predators are unlikely. Most dusky salamanders ( Desmognathus ) and Pacific giant salamanders ( Dicamptodon ) lay smaller batches of medium-sized eggs in
8804-437: The eggs inside her body until they hatch, either into larvae to be deposited in a water body, or into fully formed juveniles. In temperate regions, reproduction is usually seasonal and salamanders may migrate to breeding grounds. Males usually arrive first and in some instances set up territories . Typically, a larval stage follows in which the organism is fully aquatic. The tadpole has three pairs of external gills, no eyelids,
8928-579: The elusive reptiles later with a Geiger counter." In 1966, Stebbins produced what became his best-known book, A Field Guide to Western Reptiles and Amphibians ( Peterson Field Guides ), which Peterson called "a classic ... one of the most beautiful as well as scholarly works in the series". Stebbins was also committed to education and conservation. He made appearances on the TV series Science in Action , traveled to Asia to promote science education, and chaired
9052-462: The extensive use of drawings in teaching natural history," a tradition he later strove to continue in his own works. On June 8, 1941, Stebbins married Anna-rose Cooper, who would eventually type the text of all of Stebbins' field guides. Part of their honeymoon was spent camping in the Owens Valley of southeastern California. In 1945 Stebbins was hired an assistant professor of zoology at
9176-530: The few species of living amphibians to occur in brackish or salt water. Many salamanders do not use vocalisations, and in most species the sexes look alike, so they use olfactory and tactile cues to identify potential mates, and sexual selection occurs. Pheromones play an important part in the process and may be produced by the abdominal gland in males and by the cloacal glands and skin in both sexes. Males are sometimes to be seen investigating potential mates with their snouts. In Old World newts, Triturus spp.,
9300-414: The field" for American herpetologists. Often referred to simply as "Stebbins", the book has educated and inspired generations of naturalists and herpetologists. On the impact of the guide, professor Samuel Sweet of UC Santa Barbara stated "Before that book, if people went out to look for snakes, it was so they could gather them up to sell to pet shops or just show off to their buddies. What [Stebbins] did
9424-509: The first time we have a field guide that indicates clearly which taxonomic interpretations are tentative and where distributions and life history features remain poorly known." Concerned about the impact of over-collecting, Stebbins reduced coverage of collecting and keeping animals, and also removed a section on handling venomous snakes. The third edition, published in 2003, included 36 new species and several new paintings. Stebbins considered keeping up-to-date with current scientific literature
9548-481: The formation of thyroid hormones. Genetics may also play a part. The larvae of tiger salamanders ( Ambystoma tigrinum ), for example, develop limbs soon after hatching and in seasonal pools promptly undergo metamorphosis. Other larvae, especially in permanent pools and warmer climates, may not undergo metamorphosis until fully adult in size. Other populations in colder climates may not metamorphose at all, and become sexually mature while in their larval forms. Neoteny allows
9672-406: The four families giant salamanders , sirens , Congo eels and Proteidae , who are all aquatic and obligate paedomorphs. Some of the largest terrestrial salamanders, which goes through full metamorphosis, belongs to the family of Pacific giant salamanders , and are much smaller. Most salamanders are between 10 and 20 cm (4 and 8 in) in length. An adult salamander generally resembles
9796-704: The frogs and toads, within Batrachia . The oldest known total-group ( Caudata ) salamander is Triassurus from the Triassic of Kyrgyzstan . Further salamander fossils are known from the Middle Jurassic of England , Scotland , China , and Kazakhstan . The oldest known crown-group salamander ( Urodela ) remains uncertain but recent analyses suggest it is Valdotriton from the Late Jurassic of Spain . Salamanders are found only in
9920-449: The future. Skin secretions of the tiger salamander ( Ambystoma tigrinum ) fed to rats have been shown to produce aversion to the flavor, and the rats avoided the presentational medium when it was offered to them again. The fire salamander ( Salamandra salamandra ) has a ridge of large granular glands down its spine which are able to squirt a fine jet of toxic fluid at its attacker. By angling its body appropriately, it can accurately direct
10044-437: The ground or in the water according to species, and the female picks this up with her vent. The spermatophore has a packet of sperm supported on a conical gelatinous base, and often an elaborate courtship behavior is involved in its deposition and collection. Once inside the cloaca, the spermatozoa move to the spermatheca , one or more chambers in the roof of the cloaca, where they are stored for sometimes lengthy periods until
10168-491: The high quality of the artwork was immediately recognized, as was the quality and thoroughness of the writing. Biologist David B. Wake , then of the University of Chicago but later to work with Stebbins at Berkeley, considered the only "serious defect" to be absence of any coverage of snake-bite first aid. Wake also noted that the geographic area covered left a gap ranging from 75 miles to over 400 miles wide when paired with
10292-403: The larvae of salamanders possess these teeth. Although larval teeth are shaped like pointed cones, the teeth of adults are adapted to enable them to readily grasp prey. The crown , which has two cusps (bicuspid), is attached to a pedicel by collagenous fibers. The joint formed between the bicuspid and the pedicel is partially flexible, as it can bend inward, but not outward. When struggling prey
10416-404: The larval stage may last from days to years, depending on species. Sometimes this stage is completely bypassed, and the eggs of most lungless salamanders (Plethodontidae) develop directly into miniature versions of the adult without an intervening larval stage. By the end of the larval stage, the tadpoles already have limbs and metamorphosis takes place normally. In salamanders, this occurs over
10540-619: The larval state. The word salamander comes from Old French salamandre from Latin salamandra from Greek σαλαμάνδρα : salamándra, of uncertain, possibly, pre-Greek origin. The Greek word is used for the fire salamander . The skin lacks scales and is moist and smooth to the touch, except in newts of the Salamandridae, which may have velvety or warty skin, wet to the touch. The skin may be drab or brightly colored, exhibiting various patterns of stripes, bars, spots, blotches, or dots. Male newts become dramatically colored during
10664-829: The last few decades of the 20th century, although no direct link between the fungus and the population decline has yet been found. The IUCN made further efforts in 2005 as they established the Amphibian Conservation Action Plan (ACAP), which was subsequently followed by Amphibian Ark (AArk), Amphibian Specialist Group (ASG), and finally the umbrella organization known as the Amphibian Survival Alliance (ASA). Researchers also cite deforestation , resulting in fragmentation of suitable habitats, and climate change as possible contributory factors. Species such as Pseudoeurycea brunnata and Pseudoeurycea goebeli that had been abundant in
10788-738: The local population on the restoration of the natural habitat of these creatures. This proximity is a large factor that has impacted the survival of the axolotl, as the city has expanded to take over the Xochimilco region in order to make use of its resources for water and provision and sewage. It is farmed for use in research facilities and so may one day return to its natural habitat. The recent decline in population has substantially impacted genetic diversity among populations, making it difficult to further progress scientifically. Some genetic indiversity due to paedeomorphism in Ambystoma species such as
10912-410: The lungless salamanders ( family Plethodontidae and the clawed salamanders in the family of Asiatic salamanders ), no lungs or gills are present, and gas exchange mostly takes place through the skin, known as cutaneous respiration , supplemented by the tissues lining the mouth. To facilitate this, these salamanders have a dense network of blood vessels just under the skin and in the mouth. In
11036-471: The males are sexually dimorphic and display in front of the females. Visual cues are also thought to be important in some Plethodont species. Except for terrestrial species in the three families Plethodontidae , Ambystomatidae , and Salamandridae , salamanders mate in water. The mating varies from courtship between a single male and female to explosive group breeding. In the clade Salamandroidea , which makes up about 90% of all species, fertilization
11160-436: The man most responsible for saving what was left of the California desert. – Richard Louv , The Web of Life In the late 1960s Stebbins became concerned about the impacts that increasingly popular off-road vehicle (ORV) driving was having on desert ecosystems of southern California—witnessing environmental degradation in some of the same places he had studied during graduate school—and became actively involved in over
11284-515: The mudpuppy (Necturus) and some other species, and the Pacific giant salamanders and a few others have a large larynx and bands known as plicae vocales. The California giant salamander can produce a bark or rattle, and a few species can squeak by contracting muscles in the throat. The arboreal salamander can squeak using a different mechanism; it retracts its eyes into its head, forcing air out of its mouth. The ensatina salamander occasionally makes
11408-513: The non-specialist book A Natural History of Amphibians with former student Nathan Cohen in 1997, and revised his Field Guide to California Amphibians and Reptiles in 2012, with new contributions by Samuel McGinnis, another former student. In 2009 he produced Connecting With Nature: A Naturalist's Perspective , a book intended to help connect children with nature. He took additional art lessons, broadened his subject matter to include landscapes, African wildlife, portraits, and still lifes, and took up
11532-543: The palatable yellow-eyed salamander ( Ensatina eschscholtzii ) closely resembles the toxic California newt ( Taricha torosa ) and the rough-skinned newt ( Taricha granulosa ), whereas in other parts of its range, it is cryptically colored. A correlation exists between the toxicity of Californian salamander species and diurnal habits: relatively harmless species like the California slender salamander ( Batrachoseps attenuatus ) are nocturnal and are eaten by snakes, while
11656-461: The passing of the 1994 California Desert Protection Act . After retirement he continued to paint, collect field notes, and write books. Stebbins is commemorated in the scientific names of three species: Batrachoseps stebbinsi , the Tehachapi slender salamander; Anniella stebbinsi , a legless lizard; and Ambystoma tigrinum stebbinsi , the endangered Sonora tiger salamander. Robert Stebbins
11780-547: The previous year. He was survived by his wife and three children. Only one week before his death, he was honored in the scientific name of a newly described species of legless lizard, Anniella stebbinsi . His collected field notes, comprising over 35 bound volumes, are archived in the Museum of Vertebrate Zoology. Stebbins' book A Field Guide to Western Reptiles and Amphibians , first published in 1966 and revised in 1985, 2003, and 2018, has widely been considered "the bible of
11904-579: The prey, which is then swallowed. Though frequently feeding on slow-moving animals like snails , shrimps and worms , sirenids are unique among salamanders for having developed herbivory speciations, such as beak-like jaw ends and extensive intestines. They feed on algae and other soft-plants in the wild, and easily eat offered lettuce . Salamanders have thin skins and soft bodies, move rather slowly and might appear vulnerable to opportunistic predation, but have several effective lines of defense. Mucus coating on damp skin makes them difficult to grasp, and
12028-411: The process by which one species becomes two. Zoologist Arnold Grobman called Stebbins' research "without doubt, the most outstanding study of a genus of American salamanders that has yet appeared." The Ensatina complex has been the focus of research ever since, and is a widely used textbook example of evolutionary processes. Stebbins' early work with lizards in the southern California desert led to
12152-488: The rear. The hind limbs are extracted and push the skin farther back, before it is eventually freed by friction as the salamander moves forward with the tail pressed against the ground. The animal often then eats the resulting sloughed skin. Glands in the skin discharge mucus which keeps the skin moist, an important factor in skin respiration and thermoregulation. The sticky layer helps protect against bacterial infections and molds, reduces friction when swimming, and makes
12276-410: The recognition of predators, and courtship rituals, but is probably secondary to sight during prey selection and feeding. Salamanders have two types of sensory areas that respond to the chemistry of the environment. Olfactory epithelium in the nasal cavity picks up airborne and aquatic odors, while adjoining vomeronasal organs detect nonvolatile chemical cues, such as tastes in the mouth. In plethodonts,
12400-480: The salamander family. Research is being done on the environmental cues that have to be replicated before captive animals can be persuaded to breed. Common species such as the tiger salamander and the mudpuppy are being given hormones to stimulate the production of sperm and eggs, and the role of arginine vasotocin in courtship behaviour is being investigated. Another line of research is artificial insemination , either in vitro or by inserting spermatophores into
12524-470: The sand's surface. His Ph.D dissertation (completed in 1943) further explored the anatomical, behavioral, and physiological adaptations of the lizards. During this time he also published on the behavior of the sidewinder rattlesnake , and, with his father, produced two field guides to birds, providing illustrations to his father's text. Their first book, What Bird is That? , was pressed in the family garage. Stebbins considered his father "a pioneer of sorts in
12648-448: The sensory epithelium of the vomeronasal organs extends to the nasolabial grooves , which stretch from the nostrils to the corners of the mouth. These extended areas seem to be associated with the identification of prey items, the recognition of conspecifics , and the identification of individuals. The eyes of most salamanders are adapted primarily for vision at night. In some permanently aquatic species, they are reduced in size and have
12772-462: The shape of the foot varies according to the animal's habitat. Climbing species have elongated, square-tipped toes, while rock-dwellers have larger feet with short, blunt toes. The tree-climbing salamander ( Bolitoglossa sp.) has plate-like webbed feet which adhere to smooth surfaces by suction, while the rock-climbing Hydromantes species from California have feet with fleshy webs and short digits and use their tails as an extra limb. When ascending,
12896-429: The slimy coating may have an offensive taste or be toxic. When attacked by a predator, a salamander may position itself to make the main poison glands face the aggressor. Often, these are on the tail, which may be waggled or turned up and arched over the animal's back. The sacrifice of the tail may be a worthwhile strategy, if the salamander escapes with its life and the predator learns to avoid that species of salamander in
13020-458: The species to survive even when the terrestrial environment is too harsh for the adults to thrive on land. A general decline in living amphibian species has been linked with the fungal disease chytridiomycosis . A higher proportion of salamander species than of frogs or caecilians are in one of the at-risk categories established by the IUCN . Salamanders showed a significant diminution in numbers in
13144-432: The spermatophores from the male axolotl. It is a safe and non-invasive method that requires the collection of the spermatophores and places them into a deep freeze for preservation. Most importantly, they have found that there is only limited damage done to the spermatophores upon thawing and thus it is a viable option. As of 2013, it is a method that is being used to save not only the axolotl but also numerous other members of
13268-439: The spray for a distance of up to 80 cm (30 in). The Iberian ribbed newt ( Pleurodeles waltl ) has another method of deterring aggressors. Its skin exudes a poisonous, viscous fluid and at the same time, the newt rotates its sharply pointed ribs through an angle between 27 and 92°, and adopts an inflated posture. This action causes the ribs to puncture the body wall, each rib protruding through an orange wart arranged in
13392-406: The tail props up the rear of the body, while one hind foot moves forward and then swings to the other side to provide support as the other hind foot advances. In larvae and aquatic salamanders, the tail is laterally flattened, has dorsal and ventral fins, and undulates from side to side to propel the animal through the water. In the families Ambystomatidae and Salamandridae, the male's tail, which
13516-413: The throat, assisted by depression of the eyeballs into the roof of the mouth. Many lungless salamanders of the family Plethodontidae have more elaborate feeding methods. Muscles surrounding the hyoid bone contract to store elastic energy in springy connective tissue, and actually "shoot" the hyoid bone out of the mouth, thus elongating the tongue. Muscles that originate in the pelvic region and insert in
13640-431: The tongue are used to reel the tongue and the hyoid back to their original positions. An aquatic salamander lacks muscles in the tongue, and captures its prey in an entirely different manner. It grabs the food item, grasps it with its teeth, and adopts a kind of inertial feeding. This involves tossing its head about, drawing water sharply in and out of its mouth, and snapping its jaws, all of which tend to tear and macerate
13764-487: The tongue bulges and changes shape as it shoots forward. The protruded tongue has a central depression, and the rim of this collapses inward as the target is struck, trapping the prey in a mucus-laden trough. Here it is held while the animal's neck is flexed, the tongue retracted and jaws closed. Large or resistant prey is retained by the teeth while repeated protrusions and retractions of the tongue draw it in. Swallowing involves alternate contraction and relaxation of muscles in
13888-590: The violin, which he had studied decades earlier. His paintings have been shown and sold in galleries and museums in Berkeley, Palm Springs, and Oregon. Stebbins was a fellow of the California Academy of Sciences , which awarded him its highest honor, the Fellows Medal, in 1991. Stebbins died at age 98 at his home in Eugene, Oregon on September 23, 2013, having been in declining health over
14012-566: The war against motorized vehicles in the desert." Stebbins' efforts eventually helped secure the passing of the California Desert Protection Act of 1994 which established the Mojave National Preserve and elevated Joshua Tree and Death Valley from national monuments to more protected national parks. In 1998 Stebbins was recognized in the U.S. Congress by Representative George Miller and
14136-455: The water intermittently, and others are entirely terrestrial as adults. This group of amphibians is capable of regenerating lost limbs as well as other damaged parts of their bodies. Researchers hope to reverse engineer the regenerative processes for potential human medical applications, such as brain and spinal cord injury treatment or preventing harmful scarring during heart surgery recovery. The remarkable ability of salamanders to regenerate
14260-412: The western United States and to collect enough material to begin preparing his first amphibian field manuals. The first of these to appear was Amphibians of Western North America (1951, University of California Press), covering the U.S. and Canada roughly west of the 102nd meridian . Praised for its thoroughness as well as its illustrations, the book "unquestionably provides more information concerning
14384-495: The western part of North America. The eastern Plethodon subgenus can be further categorized into at least three major species groups which genetic analyses confirm to be clades : As of 2024 there are up to 58 species in the genus Plethodon . Most are native to eastern and central North America, with the Appalachian Mountains having the highest diversity. Seven species live along the West Coast , one ( P. idahoensis ) in
14508-662: The wildlife of Northern California. His mother, born in Switzerland and educated at the Normal School, instilled a sense of artistry in Robert, painting pictures for Robert and his siblings in her spare time. When Stebbins was seven, his family moved to the San Francisco Bay Area, where his father worked on agricultural curriculum for children and taught at the University of California, Berkeley. Around
14632-449: The work of Stebbins and others, began investigating the pineal gland in mammals, with emphasis on the effect of melatonin on activity cycles. Melatonin has since been found to influence human health. Stebbins was proud of his parietal and pineal work, calling it "possibly the single piece of research which gives me the most satisfaction." In 1949 Stebbins received a Guggenheim Fellowship that allowed him to extend his studies throughout
14756-481: The world. The Chinese giant salamander , at 1.8 m (6 ft) the largest amphibian in the world, is critically endangered , as it is collected for food and for use in traditional Chinese medicine . An environmental education programme is being undertaken to encourage sustainable management of wild populations in the Qinling Mountains and captive breeding programmes have been set up. The hellbender
14880-456: Was an American herpetologist and illustrator known for his field guides and popular books as well as his studies of reptiles and amphibians. His Field Guide to Western Reptiles and Amphibians , first published in 1966, is still considered the definitive reference of its kind, owing to both the quality of the illustrations and the comprehensiveness of the text. A professor of zoology at the University of California, Berkeley , for over 30 years, he
15004-515: Was born on March 31, 1915, in Chico, California , to parents Cyril Adelbert and Louise Stebbins ( née Beck). His father, born in Wisconsin of English descent, was an instructor at Chico State Normal School who had also published on birds and agriculture, stressing the importance of gardening in education. The oldest of seven children, young Robert grew up learning about local birds and exploring
15128-630: Was help make a transition to a similar situation as bird watching, where it became OK to just look at the animals and leave them alone." In 2017 the book was ranked #7 in BookFinder.com 's "out-of-print and in demand", a list of the most searched for out-of-print titles. In 1966, the Houghton-Mifflin Company first published A Field Guide to Western Reptiles and Amphibians as part of its Peterson Field Guide series. While including some illustrations from Stebbins' previous books,
15252-475: Was the biology of fringe-toed lizards , a group of sand-dwelling lizards of the American Southwest. For his master's degree (completed in 1942) he studied the anatomical structure of the nasal passages of the lizards, documenting in detail the looped, horseshoe-shaped structure of the nasal passages that functions as a u-trap , preventing sand grains from being inhaled while the lizards lay buried at
15376-458: Was the first curator of herpetology at the Museum of Vertebrate Zoology , a 1949 Guggenheim fellow , and author of over 70 scientific articles. His discovery of the ring species phenomenon in Ensatina salamanders is now a textbook example of speciation , and he performed extensive research on the parietal eye of reptiles. He produced nature films, supported science education in primary grades, and organized conservation efforts that aided in
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